1080P will work with a minor degradation n quality. Some of the smaller objects are not visible.
This is according to the instructions.
You can get a nice Sony smaller screen 4K UHD tv for less than $495

This is the ultimate jewelry for your dream ham shack! The Geochron Digital 4k UHD gives viewers beautiful displays of the Earth with the sunrise-sunset rendered in real-time through a small computer that plugs directly in to your TV via HDMI. The size of your display is only limited by the size of your TV, as you take in the terrestrial movement of the Earth’s orbit in sync with the Sun.

The Geochron Digital 4k UHD displays a full-featured Geochron World Clock on any 4k TV, with every mapset and lighting option available in the famous mechanical clock but at a fraction of the cost. Now in the digital format, users customize markers on the map, and recieve (with internet) real time updates.

This is the ultimate jewelry for your dream ham shack! The Geochron Digital 4k UHD gives viewers beautiful displays of the Earth with the sunrise-sunset rendered in real-time through a small computer that plugs directly in to your TV via HDMI. The size of your display is only limited by the size of your TV, as you take in the terrestrial movement of the Earth’s orbit in sync with the Sun.

The Geochron Digital 4k UHD displays a full-featured Geochron World Clock on any 4k TV, with every mapset and lighting option available in the famous mechanical clock but at a fraction of the cost. Now in the digital format, users customize markers on the map, and recieve (with internet) real time updates.